Process of burning solid fuel.



O. B. EVANS.

'PRocBss 0F BURNINGSOLID FUEL.

APPLICATION FILED MAR. 20, 1913.

OWEN BROOKE EVA-NS, 0F LANSDOWNE, PENNSYLVANIA, .SSGNOE TG THE UNITED GAS IMFROVEMENT COMPANY, OF PHILADELPHIA, EENNSYLVANIA., A CRPGRA TION OF PENNSYLVANIA.

PROCESS OF BURNNG SOLID FUEL.

Specification of Letters Patent.

Patented Feb.. 3,19145..

Application filed March 20, 1913. Serial No. 755,575.

To all whom it may concern.:

The principal object is to prevent or minimize the agglutination in the form of socalled clinker of the partly melted residuum of the combustion of a bed of coal or fuel which has a fusible ash.

-To this and other ends hereinafter set forth the invention, generally stated, con`v sists in maintaining in the fuel bed superposed zones of relatively high and low temperatures, such as will and will not melt and agglutinate the residuum or ash into clinlrer by apportioning the direction and quantity of flowv of blast through them; feeding through the hotter Zone a sufficient vquantity of unbu'rned fuel along with the residunm or ash of the burned fuel for preventing agglutination of the partly melted ashv or residuum -into clinker.; and feeding the last mentioned unburned fuel and divided residuum to the cooler zone and there burning such fuel at a temperature insufficient to agglutinate the divided residuum.

The process of the invention will be claimed at the end hereof and can be practised by means of a great variety of apparatuses and alone or in connection with other industrial processes. However, it will be described in connection with the accompanying' drawings, in Which- Figure 1, is a vertical section of one type of gas producer, or generator. Fig. 2. is a similar view of another type, and Fig. 3, is a similar view of a third type.

Referring to the drawings, the bed of fuel is shown as contained in a generator l,hav ing one or, morelfuel intakes 2, a grate 8, openings .19 for removing the ash and an olftake 8, for the products of combustion, fuel gas or the like. As shown in Figs. 1 and 2,

the grate is substantially flat and the fuel is fed into the top of the generator, While in Fig. 3, the grate is conical and the fuel is fed into the bottom of the generator by any well known type of under feed 21. Olftake connects by means of the valves l and 5 to the top and bottom respectively of the bed of fuel. does not extend into the generator beyond the lining, while in Fig. 2, it is extended by means of pipes 6 and 7 whereby the blast (either steam or air) may be admitted to the axis of the generator, and the products of combustion, fuel gas, or the like, collected from a similar point. As shown in Figs. 1, 2 and 3,*air or steam, or both, may be admittedbeloa7 the grate by means of the valved air connection 12, and the valved steam connection 13, or above the fuel bed by means of valved air connection 11 and valved steam connection 14, While in Fig. 2, in addition to these connections, additional means are provided for introducing these fluids in the fuel bed through the olftake eX- tensions 6 and 7 by means of the valved air connections 17 and 18, and the valved steam connections 15 and 16.

Zones 9, and 10 are superposed zones of respectiif'ely relatively liiglrand low temperatures; thehigh temperature Zone Ibeing locatedbetween thelow temperature Zone and that end of the fuel bed to which fuel is fed,

In Figs. 1 and 8 the olftakev for example, in `Figs. 1 and 2, the high tem-A Y Vperat-ure zone 9 is' above'the low temperature zone l0. while in Fig. 3, their positions are reversed. zontally clear across the fuel bed and may be of substantially uniform temperature throughout their extent. These zones are not sharply defined, although in fact they exist, and are maintained by proport-ioning and regulating the direction and Quantity of flouVv of blast through the fuel bed. The blast referred to is primarily intended to These zones may extend hori-V be an air blast such as is used in forced com- Roughly, 20% of the total air supplied is then admitted below the grate by connection 12, the products leaving through ofi"- take 3. 12 is `then shut off, valve 4t is closed, valve opened, and the remaining 80% of air is admitted through connection 11, pass ing down through the re to the oiftakei. 1'1, is then shut off, and roughly 40% of the total steam supplied is admitted through 14, following' the direction of the preceding blast. 14 and 5 are then closed, and 4 and 13 are opened, allowing the remaining 60% .of the steam to'travel up through the fire. 13 is then closed and blast again admitted through 12, as above described.

The type of apparatus shown in Fig. 2 is to be preferred over that in Fig. 1, since by/jadmitting all, or most of, the steam, or air,`or other fluid to the fire by means ot the pipes and 7, and subsequently withdrawing the products of combustion or fuel gas from the same pipes, there is a tendency for the iluids to pass through the aXis of the bed of fuel, eliminating the objection hitherto experienced with apparatus of the type shown in Fig. 1 in which the greater proportion of flow is next to the walls, vand hence making the entire bed of fuel more active. in ease the axis of the fire is doing too much of the work, that. part next the walls may be made more active by admitting some of the steam and air by means of the connections 1l, 12, 13 and' 1st,. Under auch conditions the maximum temperature iu zone 9 may be, for example when using coke "2800o F. and the maximum temperature of zone 10, 2000o F., both more or less. The proportions and temperatures mentioned above are given merely as an eXample, since these will vary considerably, depending upon the character of the fuel used as well as upon whether the fresh fuel is fed into the top or the bottom of the fuel bed. The telmierature inthe part of the fuel bed, for convenience referred to as the Zone 9, is sulliciently high to cause melting and agglutination' of the residuum of combustion of the fuel which has a fusible ash into masses usually called clinkers` and the temperature in the part of the fuel bed, for convenience referred to as the zone 10, is lower and is not sufliciently high to cause such agglutination, but in the zone 9 thereis present sufficient carbon for preventing agglutlnation into chnker of the fused or partially fused residuum, and the presence of this fuel in the zone 9 is insured b v does not take place.

proper feeding. The fuel last referred to travels to and is consumed in the zone 10, wherethe temperature is so low that agglutination into clinker of the divided residuum Even if the temperature in the zone 9 is sufficient to fuse lor melt the ash, there is carbon left in the material, which carbon passes into the cooler zone and is there burned because Such carbon moves through the zone 9, to take the place of the carbon burned in the zone 10, or by reason of the' removal of ash from the zone 10.

In the type of apparatus shown in Figs. 1 and 2 the feed is downward and is assisted by gravity, while in Fig. 3, the feed is upward and produced by mechanical means, It might be said that even if the conditions are favorable in thezone 9, for burning carbon, still the feed through that zone is so fast that all of the carbon in that zone is not burned. With the proper proportion of air flow the .fresiduum is substantially free from clinker'. llf the proportion of air flow` ing through the fire in the general direction of the travel of the fuel, is increased beyond the proper figure, .the combustion of fuel.

the fuel through Zone 9 is not 'sufficiently rapid to insure the presence o-fenough carbony in zone 9 to prevent the agglutination of the fused resinuum into clinker. lf the propor tion of air flowing through the fire in the general direction of the travel of the fuel is reduced below the proper amount, the correspondingl increase in the How in the opposite direction `will produce a temperature in zone where the per cent. ofv carbon is low, above that of the fusing point of the ash and agglutinate the fused residuum into clinkers.

lVhile it is notnew to blast up or down through the lire, it is believed that the proper proportie-ning of the blast to produce the result herein indicated has never before been suggested or attained.

For the sake of further description but without intending to limit the claims, it may be said that at one end of theA fuel bed there is fuel, and at the other there is a divided residuum of combustion, free, or at any rate substantially free from clinker, and that at the zone 9 there is present suflieient carbon for preventing agglutination of the fused or partly fused residuum, so that what is known as clinker is practically' absent. As an illustration and not to limit the claims, it may be said that in the zone 9, and in the case of coke, there is present about one-third carbon and two-thirds residuum. tally, it may be remarked that for economic and other well known reasons it is necessary in the combustion of fuel which has a fusible ash to raise the temperature to a point at which such ash would, if unrestrained and uncontrolled, agglutinate into masses called clinkers. By the present invention,

lncidenhowever, the existence of these high tem# fuel bed which has sufficient carbon to prevent thefused residuum from agglutinating and in that Wayclinkers are avoided, while at the same time combustion of the fuel is satisfactorily carried on. It is hardly necessary to state that to removeclinkers is a laborious operation, and the presence of clinkers interferes with combustion, so that the Yimportance of avoiding the formation of c linkers is obvious for these reasons, as Well as for maniT other reasons, well known to those skilled in the art.

I claim:

l. The process of preventing the formation of'clinkcrs in the combustion of a bed of fuel having a fusible ash7 which consists in maintaining in the bed superposed zones of Which one is at a temperature that would and the other is at a temperature that vculd not fuse ash by .apportioning the distribution and changing the direction of applicationlofthe gas making fluids in respect to the zones, and preventlng the agglutination of the fused ash into clinlier by 'feeding unconsumed carbon through the hotter zone, and burning such carbon in the cooler zone.

2. The process 0f preventing the formation of clinkers in the combustion of a bed of fuel having a fusible ash "which consists in maintaining in the bed superposed Zones of which one is at a temperature that would and the other is at a temperature that would not fuse ash by apportioning the distribution and changing the direction and place of application of the gas making uids in respect to the zones, and preventing the agglutination of the fused ash into clinlrer by feeding unconsuined carbon through the hotter Zone and burning such carbon in the cooler zonev g 3A rilhe process of preventing thev fermation of clinker in the combustion of fuel which consists in changing the direction of` application of the gas mal/ing iiuids to the bed to produce therein regions Where ash would and would not fuse, and feeding cai:- bon along with the fused ash to prevent its clinkering and thereafter burning out the carbon when the ash is not fused.

p OWEN BROOKE EVANS.

Witnesses CLIFFORD K. Cassin, FRANK E. FRENCH. 

